Presses actuated by a fluid under pressure



sep; 24, 1957 sAlvl-:s 2,807,206

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PREssE-s-AcTUATED BY A FLUID UNDER PRESSURE Filed July 17. 195s s sheets-sheet s Patented Sept. 24, 1957 PRESSES ACTUATED BY A FLUID UNDER PRESSURE Lon Saives, Billancourt, France, assigner to Regie Nationale des Usines Renault, Billancourt, France Application July 17, 1953, Serial No. 363,552 Claims priority, application France September 1, 1952 2 Claims. (Cl. 1mi- 258) This invention relates to improvements adapted to control the vertical travel of the slide or head of a hydraulic or like fluid-pressure actuated press so as to ensure the accurate parallelism between the slide or head and the stationary table of the press.

It is also within the scope of these improvements to adjust the length of the stroke of the slide by means of a preset stop.

The vertical motion of the slide or head of a pressurefluid operated press is generally obtained by means of a plurality of rams for evenly distributing the driving pressure throughout the pressure face of the slide. It has been noticed that even in modern presses the strokes of the power rams are not always strictly identical, and consequently the different portions of the slide or head travel at irregular rates and the slide is subjected to a tilting movement which is detrimental in that it involves:

(a) Abnormal wear of the guides;

(b) The necessity of providing excessive clearance in the guides;

(c) Irregular movements of the tools used and therefore a reduction in the quality of the parts produced.

There is a special type of hydraulic press utilized in the manufacture of press tools or dies. This press is a special purpose machine designed to bring the two cooperating upper and lower die parts into mutual engagement for mutual relative adjustment. In other words, this type of machine is used to cause one nished tool or die portion to contact its companion portion to be fitted to it so that the two portions may tit into each other with maximum accuracy.

As a rule, in this operation the finished tool portion is mounted on the slide or hea-d of the press and brought into engagement with the portion to bt tted to it, which is mounted on the stationary table of the press.

When the upper portion engages the lower portion, contact occurs therebetween at one or more points called high points. In this position, the slide or head of the conventional type of press will bear on these high points and will tilt in order to lind on the lower portion of the tool one or more other points to provide stability between the two tool or die portions.

The tool maker is therefore confronted with a misleading relationship since the final contact between the twoV portions does not occur at the high points alone but also includes contact by reason of the tilting or bending of the press as a result of the irregular movement Iof the main slide.

Under these circumstances, the tool makers analysis of the relationship between the two portions may be inaccurate and in trimming one of the tool portions to vbring about the desired relationship between the two portions he may remove metal from points other than the aforesaid high points, which is obviously disadvantageous and is likely to a-dversely affect the quality of the objects subsequently produced by the tool.

The improvements to which this invention relates are concerned with two mechanisms, viz. a slide control device, and a movement-limiting device which can be mounted on machines of the types mentioned, either separately or in combination, for the purpose of avoiding the drawbacks pointed out above.

The accompanying drawings, which form part of this specication, illustrate by way of example one form of embodiment of the invention. In the drawings:

Fig. 1 is a front elevational view, partly in section to show details of the hydraulic system, of a hydraulic press embodying features of the present invention;

Fig. 2 is a partial sectional view of the press shown in Fig. 1 showing the slide controlling mechanism and the slide movement limiting me-chanism of the invention, the front portion of the machine shown in Fig. 1 and one link between the guide and a rocker arm being omitted;

Fig. 3 shows the same construction illustrated in Fig. 2 with the slide in a lowered position rather than in the elevated position shown in Fig. 2.; and

Fig. 4 is a perspective View, with parts 'broken away to show details of construction of a portion of the mechanisms of the invention.

The press illustrated in the drawings (Figs. l to 3) hasl a stationary table or bed 1 with upright frame members 2 supporting an upper stationary cr-oss head 3 and a vertically movable slide 14 guided by guides 4 and movable vertically by a plurality of plungers 5 operated by lluid pressure.

The first of the above-mentioned two mechanisms of the invention comprises a slide control device consisting essentially of a pair of rockers '15, the outer arms 15a of which are operatively connected to the slide 14 through links 14 (see Fig. 4). Each of the rockers 115 is rockable about a shaft 30 supported by the frame portion of the press. The inner arms 15b of these rockers are pivotally connected through links 13 to a pilot slide 12. Pilot slide 12 is vertically movable in a guide member 21 which has two sides which are rigid with the upper stationary crosshead 3 of the press (Figs. 2 and 3).

The vertical axis of the pilot slide is the same as the axis of the primary or main slide of the press.

The links 14 are connected to the main slide 14 through adjustable fittings 142 permitting an accurate adjustment of the parallelism between the slide and the stationary table when assembling the machine. The main slide is driven by the plungers 5 actuated by the pressure fluid. The fluid is supplied to, and removed from, plungers 5 through suitable hydraulic lines 6 indicated in Fig. l, the fluid being supplied from a pump actuated in a conventional manner.

This iirst mechanism, i. e. the slide-controlling mechanism, operates as follows:

Assuming that the individualplungers 5, driven lby the pressure iluid -or by gravity to actuate the main slide 14', travel at different speeds. In a conventional press, such conditions would-cause the slide to travel irregularly and non-horizontally.

In a machine equipped with the above-described slide controlling mechanism, if one side of the slide moves downwardly through a distance Q, this movement will be transmitted through the linkage to the adjacent rocker arm and from there to one of the links 13 of the pilot slide which, in turn, will move downwardly through a distan-ce Q' proportional to the length of the rocker arms and the original displacement Q. The displacement `of the pilot slide will be affected by the length of the links 13 and 14, the position of the connectors 142, and the angle which the links make with the arms, the pilot slide, and the main slide, in addition to the length of the amis.

During this movement, the pilot slide 12 effects movement of the follower link 13, by reason of their interconnection, and the movement of the driver link is affected by the movement of the follower link 13 so that thek two links will move through the same distance in opposite directions and the opposite end of the main slide will be caused to move through the same distance Q as the rst end. The movement of the arms and links on one side of the slide 12 takes place in the opposite direction from that on the other. The movement of the links 13 and 14 simulates a portion of the movement of a connecting rod in a reciprocating engine.

Thus, except for the play in the pivotal connections of the rockers and in the links, control of the pistons and accurately parallel movement of the slide are obtained.

The second mechanism of the above-mentioned two mechanisms of the invention consists of a limiting assembly comprising a check member 11 which is vertically movable in central guide member 21 which receives at its lower end the links 13 and slidably guides at its upper end the upper cylindrical portion of pilot slide 12. The portion of guide member 21 which receives the links 13 has a flange at its upper end which is secured as by welding to the frame of the machine. The check me-mber 11 is adjustably positioned vertically to be engaged by the upper end of the pilot slide 12 at any predetermined point in its travel, the limit of the upward movement of the pilot slide being determined by the position of the check member 11. The vertical position of the check member 11 in the guide member 21 is adjusted by means of a screw and nut system. Thus, referring to Figs. 2 and 3, the check member 11 is connected to the end of a screw 23 which threadedly engages with an interiorly threaded nut, or sleeve 24, which is adapted to be rotated by a gear connected to it which in turn is driven by a gear 27 actuated by a motor 2S. The sleeve, or nut 24, is held in position by a collar 26 which is secured in any convenient means, e. g. by press fitting, to the upper end of the guide member 21. A nut 25a holds the gear wheel 2S against vertical displacement.

The rst and second mechanisms described hereinabove can be readily combined in presses of the special type previously mentioned for fitting tool portions to each other. The first mechanism according to this invention ensures the accuracy of the horizontal position of the slide. The second mechanism is intended to stop the slide 14 at exactly the desired uppermost position.

Thus, in operation, assume that the right end portion of the main slide 14' as seen in Figs. 2 and 3 is forced downwardly by some irregularity of the material engaged by the slide, then the right link 14 will move downwardly with it, drawing the right arm 15a downwardly to turn about shaft in a clockwise direction. This will cause the right arm 15b to rise, forcing right link 13 upwardly and thereby causing slide 12 to rise. When slide 12 rises, the link 13 on the left, as seen in Figs. 2 and 3, will rise, drawing left arm 15b upwardly to rotate left arm 15a in a counterclockwise direction. The left arm 15a will thus be depressed, forcing link 14 to depress the left end portion of the main slide 14 downwardly so that the original horizontal position -of the main slide is regained. The check member or stop 11 limits the extent of upward travel of pilot slide 12. As a result of the presence of the linkages the slide, the rocker arms and the shaft 30 referred to above, the extent of the downward travel of main slide 14 is correspondingly limited by the check member or stop 11. Consequently, the check member 11 should `be so placed as to limit the upward movement of pilot slide 12 to permit the displacement which will achieve this result. On the other hand, if downward movement of the right end portion of the main slide 14 described above is for some reason undesired beyond a given limit, and such downward movement is to be prevented, then this can readily be effected by suitable adjustment of the check member 11 so that, when the tendency for the right end portion of the main slide to move downwardly as a result of some irregularity of the material in the press arises, the check member will prevent upward movement of pilot slide 12 and corresponding clockwise rotation of arms 15a and 15b at the right hand side of Figs. 2 and 3. At the same time, any corresponding counter-clockwise rotation of arms 15a and 15b at the left of Figs. 2 and 3 will be prevented and the main slide 14 will remain in its desired horizontal position without the type of adjustment described above. lVarious operations can, therefore, be successfully Icarried out and movement of the slide 14 can be limited to any desired extent and in any desired manner by suitable positioning of the check member 11 so that it will engage the pilot slide 12 at the appropriate point. In order to facilitate the setting of the check member 11 there may be provided a conventional dial and linkage connecting it to the check member 11 so that the vertical position of the check member 11 in relation t-o the bottom of central guide member 21, for example, in centimeters, millimeters or other suitable units, can be readily seen by the operator. it will be apparent that other conventional indicating means may be suitably provided and such indicating means do not form part of the present invention.

For the proper operation of the above-described mechanisms, a fixed relationship between the arms 15a and 15b is unnecessary. What is necessary is that the arm 15a on one side of the slide be equal in length to that on the other side, that the arm l15b on one side of the pilot slide be equal in length to that on the other side, that the links 13 and 14 on one side of the pilot slide be equal in length to those on the other, and that the place where these links are pivotally attached be equally spaced from the vertical axis of the pilot slide.

I claim: Y

1. In a press actuated by fluid pressure, a vertically movable main slide, uid pressure means for moving said slide vertically and a device controlling the vertical travel of said slide and ensuring the constant parallelism thereof, said device comprising a central control slide, stationary guide means guiding said control slide for vertical movement, a pair of parallel rockers extending longitudinally of said main slide and pivotally supported to rock about xed parallel horizontal axes that are parallel to and equally spaced from a vertical central longitudinal plane passing through the central axis of said control slide, each of said rockers having an inner arm extending toward said plane and outer arms projecting away from said plane, links connecting said outer arms to said main slide and links connecting said inner arms to said control slide, each of said rockers and its associated connections being symmetrical with the other of said rockers and its connections with respect to said central vertical plane.

2. ln a press actuated by fluid pressure, a frame, a main slide movable vertically in said frame, said slide having ends guided by the frame, fluid pressure means for moving said main slide and a device for controlling the vertical travel of said slide comprising a central control v slide, stationary guide means guiding said control slide for rectilinear vertical movement, a single means for variably limiting the vertical movement of said control slide, means for setting said limiting means, a pair of parallel rockers extending longitudinally of said main slide and pivotally supported to rock about fixed parallel horizontal axes that are parallel to and equally spaced from a vertical central longitudinal plane passing through the central vertical axis of said control slide and disposed midway between the ends of said main slide, said axes being approximately midway between the ends of said main slide and said plane, each of said rockers having midway yof its length an inner horizontal arm projecting substantially to said plane and, near the ends of said inner arm, `outer arms projecting away from said plane and substantially the same length as said inner arm, links connecting said outer ar-ms to said -main slide adjacent the ends thereof and links connecting said inner arms to Vsaid control slide, each of said rockers and its associated connections being symmetrical with the other of said rockers and its connections with respect to said central vertical plane and said limiting means limiting the angular movement of both of said rockers.

References Cited in the le of this patent UNITED STATES PATENTS 

